A prospective randomized double-blind trial comparing ondansetron versus prochlorperazine for the prevention of nausea and vomiting in patients undergoing fractionated radiotherapy.

In a multicentre, international double-blind trial, patients undergoing courses of five or more daily radiotherapy treatments to the upper abdomen were randomized to receive either oral ondansetron 8 mg t.d.s. or oral prochlorperazine 10 mg t.d.s. throughout their radiation course in order to try to prevent nausea and vomiting. A total of 192 patients were recruited, 135 of whom were included in the efficacy analysis; of these, 70 received ondansetron and 65 prochlorperazine. Forty-three (61%) of the patients prescribed ondansetron and 23 (35%) of those given prochlorperazine had a complete response, with no emetic episodes throughout their treatment course (P = 0.002). There was, however, no significant difference between the two groups with respect to the incidence and severity of nausea. Seventeen (24%) of the patients on ondansetron and 19 (29%) of those given prochlorperazine were treatment failures, experiencing more than five emetic episodes on their worst day during the study. Both drugs were well tolerated, although constipation was seen more commonly with ondansetron.